In the prior art, conventional mold tools require very accurate tolerances to be achieved between the alignment of the sides of core and cavity insert blocks. To achieve the precise alignment, very accurate tolerances must be held on a long tolerance loop which involves not only the core and cavity insert blocks, but also elements of the mold base that are supporting the insert blocks. If the core and cavity insert blocks of a mold tool do not align precisely throughout the mold tool's life, excessive wear of mating shut out faces occurs which in turn causes a degradation in the quality of components that can be molded by that tool.
Usually, in technical mold tools in the prior art, the core insert block and cavity insert block are either recessed into pockets in the mold base or fixed onto the front face of the mold base plates. The mold base is manufactured to ensure a high precision and consistency of alignment. The prior art attempts to achieve the high precision and consistency of alignment of the insert blocks by using guide pillars and on more demanding mold tools extra alignment blocks are mounted separately onto the mold base plates. These alignment blocks are so arranged to engage with each other and control the mold base alignment before the critical mating features of the core and cavity insert blocks come into engagement with one another. This prior art alignment system requires very accurate positioning of the core and cavity insert blocks on the mold base plates to ensure that the accurate alignment control achieved in the mold base system is maintained through and including the shut off faces between the core and cavity insert blocks. The positioning of the core and cavity insert blocks is achieved by locating both the core and cavity insert blocks in accurately machined pockets or accurately keying the core and cavity insert blocks onto the mold base plates. The positioning of the insert blocks in this manner is a difficult and time consuming process and provides no compensation adjustment for wear or other factors affecting accuracy.
In other prior art mold making, for example, packaging containers and PET bottle preform molds, multiple cavity sets of core and cavity insert blocks are used on one mold base system. The individual alignment between each core and cavity insert block set is achieved by means of a conical alignment feature well known to those skilled in the art. In this alignment system, the cavity insert block is accurately located on the mold base cavity plate, particularly to ensure alignment with the runner system. The core insert block is mounted on the mold base core plate in such a way that its position can be adjusted before it is finally clamped into position with fixing screws/bolts. During the final assembly of the mold, or if adjustment is required during the life of the mold, the core insert blocks are assembled in such a manner that they can “float” that is, the screws are not fully tightened. As the two halves of the mold are bought together, each core insert block finds alignment with its mating cavity insert block by means of the individual conical alignment feature in each core and cavity insert block pair. When the mold is assembled and in a closed position, the core insert blocks are then finally clamped into position. The positioning of the insert blocks in this manner is also difficult and time consuming in the initial set-up and also during subsequent adjustment to compensate for wear or other factors affecting accuracy.
Although this conical self-alignment feature is known in some sectors of the molding industry as stated above, for example, packaging containers and PET bottle preform molds, a similar solution is not satisfactory and suitable for use with technical molds such as the molds used to produce products and parts in the telecom sectors.
Accordingly, it is an object of the present invention to provide an alignment system for core and cavity insert block pairs that overcomes the problems and drawbacks of prior art alignment systems.